Akademik Veri Yönetim Sistemi
Heat Transfer Research, cilt.54, sa.3, ss.37-50, 2022 (SCI-Expanded)
In this study, the effects of different pipe inserts on the thermal efficiency of the system and the optimum operating conditions in a pipe exposed to direct and indirect, reflected from a parabolic concentrator, solar radiation were investigated experimentally and numerically. Experiments were carried out with three different factors (pipe insert array, radiation, and Re values) and four levels. The experimental plan was created by the Taguchi method in L-16 array with two repetitions and the conditions that make the thermal efficiency optimum were investigated. First, the pipe insert was designed and manufactured. As a result of the experiments, the highest thermal efficiency was determined to be achieved with the #3 pipe insert (with 4-cm spacing), under 700 W/m2 irradiance and at 1000 Re number. Then, the situation with the optimum conditions was modeled with the ANSYS Fluent and velocity contours, temperature contours, and pressure changes related to the flow and pipe insert were analyzed. In the case the novel pipe inserts designed in the scope of this study were employed, the thermal efficiency was found to have increased by approximately 58.38%, even under laminar flow conditions. The comparisons have revealed that the experimental and numerical results were in good agreement.